Organic Light-Emitting Diode Display with Optical Cavities

This application claims the benefit of U.S. provisional patent application No. 63/683,158, filed Aug. 14, 2024, which is hereby incorporated by reference herein in its entirety.

This relates generally to electronic devices, and, more particularly, to electronic devices with displays.

Electronic devices often include displays. For example, an electronic device may have an organic light-emitting diode (OLED) display based on organic light-emitting diode pixels. In this type of display, each pixel includes a light-emitting diode and transistors for controlling application of a signal to the light-emitting diode to produce light. The light-emitting diodes may include OLED layers positioned between an anode and a cathode. To emit light from a given pixel in an organic light-emitting diode display, a voltage may be applied to the anode and the cathode of the given pixel.

Some OLED pixels may include microcavity OLED pixels, where OLED layers are covered by a partially transparent layer to form an optical cavity. The thickness of the optical cavity may be tuned so that light of a selected wavelength is emitted with high efficiency. However, if care is not taken, OLED pixels of this type may have non-uniform thicknesses, may have smaller than desired aperture ratios, may have lower than desired efficiency, and/or may require complex manufacturing processes.

It is within this context that the embodiments herein arise.

A display may include a plurality of pixels. The display may include a substrate, a reflective conductive layer with a first plurality of discrete portions on the substrate, a first transparent conductive layer with a second plurality of discrete portions, a second transparent conductive layer with a third plurality of discrete portions, and a dielectric spacer layer with a fourth plurality of discrete portions. Each one of a first subset of the plurality of pixels has a respective anode stack that comprises a respective one of the first plurality of discrete portions, a respective one of the second plurality of discrete portions, a respective one of the third plurality of discrete portions, and a respective one of the fourth plurality of discrete portions that is interposed between the respective one of the second plurality of discrete portions and the respective one of the third plurality of discrete portions.

A display may include a plurality of pixels. The display may include a substrate having a plurality of trenches, a layer that overlaps the substrate and that includes a plurality of overhang portions that overlap the plurality of trenches and define a plurality of undercuts, a reflective conductive layer with a first plurality of discrete portions on the layer and a second plurality of discrete portions in the plurality of trenches, and a transparent conductive layer with a third plurality of discrete portions on the reflective conductive layer. Each one of the plurality of pixels may include an anode stack that includes a respective one of the first plurality of discrete portions and a respective one of the third plurality of discrete portions.

A display may include a plurality of pixels. A pixel in the plurality of pixels may include a reflective anode portion, a transparent anode portion that is electrically connected to the reflective anode portion, organic light-emitting diode layers that overlap the transparent anode portion, the transparent anode portion being interposed between the reflective anode portion and the organic light-emitting diode layers, and a cathode that overlaps the organic light-emitting diode layers. The transparent anode portion may extend past an edge of the reflective anode portion to create an undercut under the transparent anode portion.

1 FIG. 10 10 An illustrative electronic device of the type that may be provided with a display is shown in. Electronic devicemay be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user's head, or other wearable or miniature device, a display, a computer display that contains an embedded computer, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, or other electronic equipment. Electronic devicemay have the shape of a pair of eyeglasses (e.g., supporting frames), may form a housing having a helmet shape, or may have other configurations to help in mounting and securing the components of one or more displays on the head or near the eye of a user.

1 FIG. 10 16 10 16 16 10 As shown in, electronic devicemay include control circuitryfor supporting the operation of device. Control circuitrymay include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access memory), etc. Processing circuitry in control circuitrymay be used to control the operation of device. The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application-specific integrated circuits, etc.

10 12 10 10 12 10 12 10 12 Input-output circuitry in devicesuch as input-output devicesmay be used to allow data to be supplied to deviceand to allow data to be provided from deviceto external devices. Input-output devicesmay include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of deviceby supplying commands through input resources of input-output devicesand may receive status information and other output from deviceusing the output resources of input-output devices.

12 14 14 14 14 14 14 14 14 14 10 14 Input-output devicesmay include one or more displays such as display. Displaymay be a touch screen display that includes a touch sensor for gathering touch input from a user or displaymay be insensitive to touch. A touch sensor for displaymay be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. A touch sensor for displaymay be formed from electrodes formed on a common display substrate with the display pixels of displayor may be formed from a separate touch sensor panel that overlaps the pixels of display. If desired, displaymay be insensitive to touch (i.e., the touch sensor may be omitted). Displayin electronic devicemay be a head-up display that can be viewed without requiring users to look away from a typical viewpoint or may be a head-mounted display that is incorporated into a device that is worn on a user's head. If desired, displaymay also be a holographic display used to display holograms.

16 10 10 16 14 Control circuitrymay be used to run software on devicesuch as operating system code and applications. During operation of device, the software running on control circuitrymay display images on display.

2 FIG. 2 FIG. 14 14 26 26 14 is a diagram of an illustrative display. As shown in, displaymay include layers such as substrate layer. Substrate layers such as layermay be formed from rectangular planar layers of material or layers of material with other shapes (e.g., circular shapes or other shapes with one or more curved and/or straight edges). The substrate layers of displaymay include glass layers, polymer layers, silicon layers, composite films that include polymer and inorganic materials, metallic foils, etc.

14 22 28 22 28 28 22 22 28 28 14 22 14 Displaymay have an array of pixelsfor displaying images for a user such as pixel array. Pixelsin arraymay be arranged in rows and columns. The edges of arraymay be straight or curved (i.e., each row of pixelsand/or each column of pixelsin arraymay have the same length or may have a different length). There may be any suitable number of rows and columns in array(e.g., ten or more, one hundred or more, or one thousand or more, etc.). Displaymay include pixelsof different colors. As an example, displaymay include red pixels, green pixels, and blue pixels. Pixels of other colors such as cyan, magenta, and yellow might also be used.

20 28 20 20 20 20 20 14 20 14 2 FIG. 2 FIG. Display driver circuitrymay be used to control the operation of pixels. Display driver circuitrymay be formed from integrated circuits, thin-film transistor circuits, and/or other suitable circuitry. Illustrative display driver circuitryofincludes display driver circuitryA and additional display driver circuitry such as gate driver circuitryB. Gate driver circuitryB may be formed along one or more edges of display. For example, gate driver circuitryB may be arranged along the left and right sides of displayas shown in.

2 FIG. 1 FIG. 2 FIG. 20 24 24 10 16 20 14 20 14 20 14 10 As shown in, display driver circuitryA (e.g., one or more display driver integrated circuits, thin-film transistor circuitry, etc.) may contain communications circuitry for communicating with system control circuitry over signal path. Pathmay be formed from traces on a flexible printed circuit or other cable. The control circuitry may be located on one or more printed circuits in electronic device. During operation, control circuitry (e.g., control circuitryof) may supply circuitry such as a display driver integrated circuit in circuitrywith image data for images to be displayed on display. Display driver circuitryA ofis located at the top of display. This is merely illustrative. Display driver circuitryA may be located at both the top and bottom of displayor in other portions of device.

22 20 20 30 14 22 2 FIG. To display the images on pixels, display driver circuitryA may supply corresponding image data to data lines D while issuing control signals to supporting display driver circuitry such as gate driver circuitryB over signal paths. With the illustrative arrangement of, data lines D run vertically through displayand are associated with respective columns of pixels.

20 26 14 22 14 Gate driver circuitryB (sometimes referred to as gate line driver circuitry or horizontal control signal circuitry) may be implemented using one or more integrated circuits and/or may be implemented using thin-film transistor circuitry on substrate. Horizontal control lines G (sometimes referred to as gate lines, scan lines, emission control lines, etc.) run horizontally across display. Each gate line G is associated with a respective row of pixels. If desired, there may be multiple horizontal control lines such as gate lines G associated with each row of pixels. Individually controlled and/or global signal paths in displaymay also be used to distribute other signals (e.g., power supply signals, etc.).

20 14 20 20 30 22 28 20 20 22 22 14 22 26 20 Gate driver circuitryB may assert control signals on the gate lines G in display. For example, gate driver circuitryB may receive clock signals and other control signals from circuitryA on pathsand may, in response to the received signals, assert a gate line signal on gate lines G in sequence, starting with the gate line signal G in the first row of pixelsin array. As each gate line is asserted, data from data lines D may be loaded into a corresponding row of pixels. In this way, control circuitry such as display driver circuitryA andB may provide pixelswith signals that direct pixelsto display a desired image on display. Each pixelmay have a light-emitting diode and circuitry (e.g., circuitry on substrate) that responds to the control and data signals from display driver circuitry.

20 14 Gate driver circuitryB may include blocks of gate driver circuitry such as gate driver row blocks. Each gate driver row block may include circuitry such output buffers and other output driver circuitry, register circuits (e.g., registers that can be chained together to form a shift register), and signal lines, power lines, and other interconnects. Each gate driver row block may supply one or more gate signals to one or more respective gate lines in a corresponding row of the pixels of the array of pixels in the active area of display.

22 28 22 38 34 36 38 32 38 40 22 38 36 38 38 3 FIG. 3 FIG. A schematic diagram of an illustrative pixel circuit of the type that may be used for each pixelin arrayis shown in. As shown in, display pixelmay include light-emitting diode. A positive power supply voltage ELVDD may be supplied to positive power supply terminaland a ground power supply voltage ELVSS may be supplied to ground power supply terminal. Diodehas an anode (terminal AN) and a cathode (terminal CD). The state of drive transistorcontrols the amount of current flowing through diodeand therefore the amount of emitted lightfrom display pixel. Cathode CD of diodeis coupled to ground terminal, so cathode terminal CD of diodemay sometimes be referred to as the ground terminal for diode.

32 22 32 32 33 33 14 22 33 32 32 40 38 14 32 3 FIG. 3 FIG. To ensure that transistoris held in a desired state between successive frames of data, display pixelmay include a storage capacitor such as storage capacitor Cst. The voltage on storage capacitor Cst is applied to the gate of transistorat node A to control transistor. Data can be loaded into storage capacitor Cst using one or more switching transistors such as switching transistor. When switching transistoris off, data line D is isolated from storage capacitor Cst and the gate voltage on terminal A is equal to the data value stored in storage capacitor Cst (i.e., the data value from the previous frame of display data being displayed on display). When gate line G (sometimes referred to as a scan line) in the row associated with display pixelis asserted, switching transistorwill be turned on and a new data signal on data line D will be loaded into storage capacitor Cst. The new signal on capacitor Cst is applied to the gate of transistorat node A, thereby adjusting the state of transistorand adjusting the corresponding amount of lightthat is emitted by light-emitting diode. If desired, the circuitry for controlling the operation of light-emitting diodes for display pixels in display(e.g., transistors, capacitors, etc. in display pixel circuits such as the display pixel circuit of) may be formed using other configurations (e.g., configurations that include circuitry for compensating for threshold voltage variations in drive transistor, etc.). The display pixel may include additional switching transistors, emission transistors in series with the drive transistor, etc. Capacitor Cst may be positioned at other desired locations within the pixel (e.g., between the source and gate of the drive transistor). The display pixel circuit ofis merely illustrative.

4 FIG. 4 FIG. 14 26 26 26 22 22 22 is a cross-sectional side view of an illustrative display with organic light-emitting diode display pixels. As shown, displaymay include a substrate. Substratemay be formed from glass, plastic, polymer, silicon, or any other desired material. Substratemay include transistor circuitry for applying control signals to the pixels. The transistor circuitry may include bulk transistors (where transistors are formed on the surface of a semiconductor substrate such as a silicon substrate). Another option is for the transistor circuitry to include thin-film transistors (TFTs), where a thin semiconductor film layer (e.g., formed from poly-crystalline or amorphous silicon) is formed on an insulating substrate (e.g., a glass or plastic substrate). In general, the OLED pixels described herein may include any desired combination of thin-film transistors and bulk transistors.shows a red pixel-R, a blue pixel-B, and a green pixel-G.

42 42 42 42 26 Anodessuch as anodes-R,-G, and-B may be formed on substrate.

42 42 42 45 54 45 45 45 45 54 45 54 14 14 14 22 3 FIG. Anodes-R,-G, and-B may be formed from conductive material and may be covered by OLED layersand cathode. OLED layersmay include one or more layers for forming an organic light-emitting diode. For example, layersmay include one or more of a hole-injection layer (HIL), a hole-transport layer (HTL), an electron-block layer (EBL), an emissive layer (EML), an electron-transport layer (ETL), an electronic-injection layer (EIL), and a charge generation layer (CGL). OLED layersmay form a plurality of single diodes or a plurality of tandem diodes. OLED layersmay be formed from white OLED layers (e.g., OLED layers configured to emit white light), combinations of red, green, blue, and/or yellow OLED layers, etc. Cathodemay be a conductive layer formed on the OLED layers. Cathode layermay form a common cathode terminal (see, e.g., cathode terminal CD of) for all diodes in display. Each anode in displaymay be independently controlled, so that each diode in displaycan be independently controlled. This allows each pixelto produce an independently controlled amount of light.

54 42 45 45 22 22 22 14 54 44 4 FIG. 4 FIG. 4 FIG. In some OLED displays, cathodeis entirely (or almost entirely) transparent and anodesmay be in direct contact with OLED layers. The display of, however, uses an optical cavity to enhance efficiency and color purity in the display. Using optical cavities as inallows for uniform white OLED layersto provide red, green, and blue light from red pixel-R, green pixel-G, and blue pixel-B respectively. An optical cavity may be formed by reflective layers within the display that are formed on either side of the OLED layers. By tuning the thickness of the optical cavity that includes the OLED layers, each pixel may be optimized to have high emission at a desired wavelength. To form an optical cavity of this type, displayinincludes a partially transparent cathode layerand additional anode portions.

54 54 54 54 54 Cathode layermay be formed from a partially transparent conductive material. In one illustrative example, cathode layermay be formed from a combination of magnesium (Mg) and silver (Ag). Cathode layermay be formed form any other desired conductive material or combination of conductive materials. Cathodemay transmit less than 90% of light, may transmit less than 80% of light, may transmit less than 70% of light, may transmit less than 60% of light, may transmit less than 50% of light, may transmit more than 40% of light, may transmit more than 50% of light, may transmit more than 60% of light, may transmit between 40% and 80% of light, may transmit between 45% and 60% of light, may transmit between 60% and 70% of light, may transmit between 50% and 75% of light, etc. Cathodemay reflect more than 10% of light, may reflect more than 20% of light, may reflect more than 30% of light, may reflect more than 40% of light, may reflect more than 50% of light, may reflect more than 60% of light, may reflect less than 50% of light, may reflect less than 60% of light, may reflect between 20% and 60% of light, may reflect between 40% and 55% of light, may reflect between 30% and 40% of light, may reflect between 25% and 50% of light, etc.

54 42 42 42 42 42 42 42 42 Cathode layermay define a first boundary for the optical cavity. The other boundary of the optical cavity may be set by anode(sometimes referred to as anode portion, reflective anode portion, reflective anode structure, etc.). Anodes-R,-G, and-B may be formed from a highly reflective material such as an aluminum copper (AlCu) alloy, a silver alloy (a combination of silver and at least one other material such as copper, germanium, palladium, etc.), or any other desired conductive material. Each anodemay reflect more than 70% of light (e.g., visible light), more than 80% of light, more than 90% of light, more than 95% of light, more than 99% of light, etc.

42 45 42 54 42 54 42 54 22 48 42 54 22 48 42 54 22 48 42 54 4 FIG. Additional layers may be formed over anodesbetween the anodes and OLED layers. However, these additional layers may be transparent and therefore do not disrupt the optical cavity. Because the additional layers are transparent, the boundaries of the optical cavity are still determined by the reflective anodeand cathode. The presence of the additional transparent layers between anodeand cathodemay result in an increased distance between the reflective anodeand cathode(because the OLED thickness is uniform).shows how pixel-R has an optical cavity with thickness-R between anode-R and cathode. Pixel-G has an optical cavity with thickness-G between anode-G and cathode. Pixel-B has an optical cavity with thickness-B between anode-B and cathode.

54 42 4 FIG. Each optical cavity thickness is tuned to optimize emission of the desired color of light for that pixel. For a given optical cavity thickness, light of a given wavelength will resonate due to multiple reflections off of the walls (e.g., cathodeand anode) of the optical cavity. The increased emission at the given wavelength caused by resonance within the optical cavity may be referred to as a microcavity effect. Pixels that are optimized to induce this effect (such as the pixels in) may be referred to as microcavity OLED pixels.

22 48 22 48 22 48 48 48 48 48 Pixel-R has an optical cavity thickness-R that maximizes emission of red light. Pixel-G has an optical cavity thickness-G that maximizes emission of green light. Pixel-B has an optical cavity thickness-B that maximizes emission of blue light. Blue light has a shorter wavelength than green light, which has a shorter wavelength than red light. Generally, the thickness of the optical cavity may be proportional to the wavelength of the type of light that is intended to be emitted. Therefore, thickness-B is less than thickness-G and thickness-G is less than thickness-R. This example is merely illustrative and does not necessarily hold true for all display designs, as other factors such as the node of the cavity may influence the optical cavity.

44 22 44 22 44 22 44 44 44 44 44 44 48 42 54 4 FIG. The thickness of each optical cavity is therefore tuned to optimize emission of light. However, changing the thickness of each optical cavity may present difficulties during manufacturing. To reduce complexity and cost in manufacturing microcavity OLED displays, additional anode portionsmay be included in each pixel. As shown in, red pixel-R has an additional anode portion-R, green pixel-G has an additional anode portion-G, and blue pixel-B has an additional anode portion-B. These additional anode portions(sometimes referred to as supplementary anodes, anodes, transparent anodes, transparent anode structures, etc.) may be formed from a transparent conductive material. The additional anode portions may be formed from a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or any other desired transparent conductive material. Because the additional anodes are transparent, they may be used to tune the optical cavity thicknessof the pixels without disrupting the optical cavity between reflective anodeand cathode.

66 A pixel definition layermay be formed between each pixel. The pixel definition layer may be formed from a non-conducting material and may be interposed between adjacent anodes of the display. The pixel definition layer may be formed from a non-conductive material (that is either opaque or transparent) and may have openings in which the anodes are formed, thereby defining the area of each pixel.

44 42 50 14 50 42 22 50 42 22 50 42 22 50 50 50 50 50 50 4 FIG. One or more additional layers may be included between anode portionand anode portionin each pixel. As shown in, dielectric spacers(sometimes referred to as spacers, dielectric layers, etc.) are included in display. A first dielectric spacer-R is formed over anode-R in red pixel-R. A second dielectric spacer-G is formed over anode-G in green pixel-G. A third dielectric spacer-B is formed over anode-B in blue pixel-B. It should be noted that multiple dielectric layers may be used to make up each one of dielectric spacers. In some cases, a single dielectric layer may be shared between multiple dielectric spacers. For example, a first dielectric layer may form a portion of spacer-R and the entirety of spacer-G. In this case, spacer-R may include a second dielectric layer to increase the thickness of the overall spacer-R relative to spacer-G.

50 44 50 44 50 Dielectric spacersas well as supplemental anodesmay all be transparent or substantially transparent. This allows the layers to serve as spacers that can have thicknesses chosen to tune the thickness of the optical cavity for each pixel. Dielectric spacersas well as supplemental anodesmay transmit more than 90% of incident light, more than 95% of incident light, more than 99% of incident light, more than 99.9% of incident light, etc. Dielectric spacersmay be formed from one or more layers of silicon dioxide, silicon oxynitride, another desired oxide material, silicon nitride, or any other desired transparent material.

50 48 45 44 45 56 22 56 22 56 22 4 FIG. Dielectric spacersserve as spacer structures that allow tuning of cavity thicknessfor each pixel. For case of manufacturing, it is desirable for a uniform thickness white OLED layerto be formed over each supplemental anode. This way, OLED layersmay be formed in a single deposition step instead of being patterned to have different thicknesses and/or different color OLED material for each pixel. As shown in, the OLED thickness-R of pixel-R, the OLED thickness-G of pixel-G, and the OLED thickness-B of pixel-B are approximately (e.g., within 5% of) the same.

50 44 4 FIG. Without dielectric spacersand supplemental anodes, having a uniform thickness OLED layer would result in the optical cavity thickness of each pixel being the same. Including dielectric spacers and supplemental anodes as inallows for the optical cavity thickness to be tuned for a desired color.

44 42 60 50 44 42 60 62 64 50 44 42 50 44 42 4 FIG. 4 FIG. Supplemental anodesmay be electrically connected to anodes. As shown in, a viamay be formed that extends through dielectric spacer-R to electrically connect anode portion-R to anode portion-R. In, viaincludes a filler portion(that may be conductive or non-conductive) and a conductive liner. Another via having the same structure (e.g., with a conductive portion and a conductive liner) is also formed through dielectric spacer-G to electrically connect supplemental anode-G to anode-G. Another via having the same structure (e.g., with a conductive portion and a conductive liner) is also formed through dielectric spacer-B to electrically connect supplemental anode-B to anode-B.

14 44 44 44 50 Each layer in displaymay have any desired thickness. In some arrangements, supplemental anode portions-R,-G, and-B may have the same thickness (e.g., within 5%, within 3%, within 1%, etc.). Each supplemental anode portion may have a thickness of less than 100 nanometers, less than 50 nanometers, less than 30 nanometers, less than 20 nanometers, less than 15 nanometers, less than 10 nanometers, greater than 5 nanometers, between 5 and 50 nanometers, between 5 and 100 nanometers, etc. Similarly, each one of dielectric spacersmay have any desired thickness (e.g., less than 100 nanometers, less than 50 nanometers, less than 30 nanometers, less than 20 nanometers, less than 15 nanometers, less than 10 nanometers, greater than 5 nanometers, between 5 and 50 nanometers, between 5 and 100 nanometers, etc.).

22 44 50 70 48 22 44 50 70 48 22 44 50 70 48 70 22 70 22 70 22 42 The supplemental anode and underlying layers between the supplemental anode and anode may be referred to as an anode stack. For example, pixel-R has an anode stack that includes supplemental anode-R and dielectric spacer-R. The total thickness-R of the anode stack is tuned to determine the total optical cavity thickness-R. Pixel-G has an anode stack that includes supplemental anode-G and dielectric spacer-G. The total thickness-G of the anode stack is tuned to determine the total optical cavity thickness-G. Pixel-B has an anode stack that includes supplemental anode-B and dielectric spacer-B. The total thickness-B of the anode stack is tuned to determine the total optical cavity thickness-B. In one arrangement, the thickness-R of the anode stack of red pixel-R may be between 100 and 200 nanometers, the thickness-G of the anode stack of green pixel-G may be between 70 and 100 nanometers, and the thickness-B of the anode stack of blue pixel-B may be between 10 and 30 nanometers. These thickness values are merely illustrative. Each anode stack may have any desired thickness (e.g., greater than 200 nanometers, between 100 nanometers and 150 nanometers, between 50 and 125 nanometers, less than 100 nanometers, less than 50 nanometers, less than 25 nanometers, less than 20 nanometers, etc.). The reflective anode portionmay also sometimes be referred to as being part of the anode stack for a given pixel.

4 FIG. 45 22 22 22 22 22 22 The example ofin which white OLED layersare uniformly deposited for pixels-R,-G, and-B is merely illustrative. In some designs, each pixel may have corresponding OLED layers of that color. For example, red pixel-R may have red OLED layers (e.g., OLED layers that emit red light), green pixel-G may have green OLED layers (e.g., OLED layers that emit green light), and blue pixel-B may have blue OLED layers (e.g., OLED layers that emit blue light). This type of arrangement may offer efficiency improvements at the cost of increased manufacturing complexity.

62 60 44 44 22 62 60 22 64 60 62 42 64 44 42 60 Filler portionof each viamay optionally be formed from the same material as supplemental anode portions. For example, if supplemental anode-R for pixel-R is formed from indium tin oxide, filler portionof viain pixel-R may also be formed from indium tin oxide. In some cases, conductive linermay be included in the viato prevent corrosion (caused by interaction between filler portionand anode). Alternatively, if the via material is compatible with the anode material(s), conductive linermay be omitted from the via and the via may include a single conductive material that is in direct contact with transparent anode structureand reflective anode structure. Viamay include conductive materials such as titanium nitride, indium tin oxide, a combination of titanium nitride and indium tin oxide, etc.

42 42 In some cases, anodesmay be formed from an aluminum alloy such as aluminum copper (AlCu). However, a silver alloy may instead be used as the material for anodes. The silver alloy may have an increased reflectance relative to the aluminum copper.

28 To increase the aperture of the pixels in pixel array, it may be desirable to reduce the distance between adjacent anodes. Aperture ratio is the ratio of the light sensitive area of a pixel to the total area of that pixel. Mitigating anode-to-anode spacing may increase the aperture ratio of the pixels, which mitigates screen door effect.

28 42 26 4 FIG. 5 9 FIGS.- To mitigate anode-to-anode spacing for increased aperture ratio and resolution in pixel array, reflective anode portionsmay be electrically isolated by trenches in an underlying substrate. The reflective anode portions ofmay be formed using wet etching techniques. However, these types of wet etching techniques may have minimum anode-to-anode spacing requirements that are larger than desired. In the examples of, trenches in substrateare used to electrically isolate reflective anode portions for different pixels.

5 FIG. 26 110 110 26 22 102 26 42 102 102 102 26 26 As shown in, substratehas a plurality of trenches. Each trenchmay be formed in substratebetween adjacent pixelsin the pixel array. The display also includes an overhang layerthat is interposed between the substrateand the reflective anode portions. Overhang layermay be formed from a dielectric material such as silicon dioxide, silicon nitride, silicon oxynitride, titanium oxide, aluminum oxide, etc. Overhang layermay instead comprise a conductive material such as titanium, molybdenum, etc. In yet another possible arrangement, overhang layermay be formed from polyimide and may be formed integrally with substrate. In other words, substratemay be patterned to define the overhang portions and corresponding undercuts.

102 26 26 102 26 14 26 110 112 102 114 112 114 114 116 112 26 110 5 FIG. 5 FIG. The majority of overhang layermay be formed an upper surface of substrateand is in direct contact with the upper surface of substrate. Overhang layermay extend past substratein a direction parallel to the plane of display(e.g., within the XY-plane of). As shown in, overhang layer has an edge that is separated from the edge of substrate(and trench) by distance. This overhang region of overhang layerdefines an undercut. Distancemay be referred to as the width of undercut. Undercutmay have a heightdefined by the separation between the lower surface of overhang layerand the surface of substratethat defines trench.

110 114 102 42 42 42 42 114 42 42 42 42 42 42 42 42 42 42 42 110 5 FIG. Each trenchtherefore has two associated undercutsdefined by overhang layerand sidewalls of the trench. Reflective anode portions-R,-G, and-B may be formed from a conductive layer. Each undercutmay create a discontinuity in conductive layerduring deposition of conductive layerover the display during manufacturing of the display. The discontinuities in the reflective conductive layercause the conductive layerto have discrete portions that are electrically isolated from one another. A first electrically isolated portion of conductive layerforms reflective anode portion-R for a red pixel, a second electrically isolated portion of conductive layerforms reflective anode portion-G for a green pixel, and a third electrically isolated portion of conductive layerforms reflective anode portion-B for a blue pixel. There may also be a portion of conductive layerformed in each trench, as shown in.

5 9 FIGS.- 4 FIG. 110 14 Each one ofshows how trenchesmay create electrically isolated reflective anode portions for pixels in display. Reflective anode portions formed using trenches in this manner may have a smaller anode-to-anode spacing compared to as in, thus increasing aperture ratio for the pixels.

5 9 FIGS.- 4 FIG. 45 54 In each one of, uniform OLED layersare formed over the red, blue, and green pixels in the pixel array. Cathodeis formed over the OLED layers. As discussed in connection with, the cavity thickness of each pixel may be selected to improve efficiency at a particular wavelength of light. Including different cavity thicknesses for each color pixel in the display may improve the efficiency of the display but may require additional manufacturing steps. Therefore, displays may sometimes have the same cavity thickness for all of the pixels in the pixel array (e.g., a one-cavity arrangement). Some displays may have two different cavity thicknesses for all of the pixels in the pixel array (e.g., a two-cavity arrangement). Some displays may have three different cavity thicknesses for all of the pixels in the pixel array (e.g., a three-cavity arrangement). When the display has three different cavity thicknesses, color filter elements may optionally be omitted from the display. When the display has one cavity thickness or two different cavity thicknesses, color filter elements may be included over some or all of the pixel colors in the pixel array of the display.

5 FIG. 5 FIG. 5 FIG. 14 44 22 22 22 22 22 22 22 22 22 shows an example of a one-cavity arrangement for display. As shown in, a transparent anode portionof the same thickness is included in the red pixel-R, the blue pixel-B, and the green pixel-G. The cavity thickness of red pixel-R, blue pixel-B, and green pixel-G are therefore the same in. Red pixel-R may include a red color filter element, green pixel-G may include a green color filter element, and blue pixel-B may include a blue color filter element.

6 FIG. 6 FIG. 14 44 1 22 22 22 44 2 22 22 22 44 3 22 22 22 22 44 1 44 2 44 3 22 44 1 44 2 22 44 1 22 22 22 22 shows an example of a three-cavity arrangement for display. As shown in, a first transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, and a portion in blue pixel-B. A second transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, but no portion in blue pixel-B. A third transparent conductive layer-is patterned to include a portion in red pixel-R but no portions in green pixel-G and blue pixel-B. With this arrangement, the red pixel-R has a transparent anode portion defined by layers-,-, and-. The green pixel-G has a transparent anode portion defined by layers-and-. The blue pixel-B has a transparent anode portion defined by layer-. The red pixel-R therefore has a thicker optical cavity than green pixel-G and green pixel-G has a thicker optical cavity than blue pixel-B.

7 FIG. 7 FIG. 14 44 1 22 22 22 44 2 22 22 22 22 44 1 22 44 1 44 2 22 44 1 44 2 shows an example of a two-cavity arrangement for display. As shown in, a first transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, and a portion in blue pixel-B. A second transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in blue pixel-B, but no portion in green pixel-G. The green pixel-G has a transparent anode portion defined by layer-. The blue pixel-B has a transparent anode portion defined by layers-and-. The red pixel-R has a transparent anode portion defined by layers-and-. The red and blue pixels therefore have optical cavities of a first thickness whereas the green pixel has an optical cavity with a second thickness that is less than the first thickness.

8 FIG. 8 FIG. 14 44 1 22 22 22 44 2 22 22 22 104 22 22 22 104 44 1 44 2 shows an example of a two-cavity arrangement for display. As shown in, a first transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, and a portion in blue pixel-B. A second transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in blue pixel-B, but no portion in green pixel-G. A dielectric spaceris patterned to include a portion in red pixel-R, a portion in blue pixel-B, but no portion in green pixel-G. Dielectric spaceris interposed between transparent conductive layers-and-. Each dielectric spacer may be formed from a dielectric material such as silicon dioxide, silicon nitride, silicon oxynitride, titanium oxide, aluminum oxide, etc.

8 FIG. 22 44 1 22 44 1 44 2 104 22 44 1 44 2 104 In, the green pixel-G has a transparent anode portion defined by layer-. The blue pixel-B has a transparent anode portion defined by layers-,-, and. The red pixel-R has a transparent anode portion defined by layers-,-, and. The red and blue pixels therefore have optical cavities of a first thickness whereas the green pixel has an optical cavity with a second thickness that is less than the first thickness.

8 FIG. 44 1 44 2 108 108 104 44 1 44 2 108 44 1 44 2 In, transparent conductive layers-and-within a given pixel may be electrically connected in a contact region. Outside of contact region, dielectric spaceris interposed between layers-and-. Inside contact region, layers-and-are in direct physical and electrical contact.

44 1 44 2 44 1 44 2 22 22 14 44 1 44 2 106 22 22 44 1 44 2 106 106 44 1 44 2 106 106 106 9 FIG. 9 FIG. 8 FIG. 9 FIG. To improve the robustness of the physical and electrical contact between layers-and-, a separate conductive layer may be included to electrically connect layers-and-in pixels-R and-B.is a cross-sectional side view of a two-cavity arrangement for displaywith a conductive layer that electrically connects layers-and-. The display ofis similar to the display ofand duplicate components will not be describe herein for simplicity. As shown in, conductive contactmay be included in red and blue pixels-R and-B to electrically connect layers-and-. Conductive contactmay sometimes be referred to as a bridge contact, metal bridge, etc. Each conductive contactmay be in direct physical and electrical contact with both transparent conductive layer-and transparent conductive layer-. Conductive contactsmay be formed from molybdenum, titanium, or another desired conductive material. Conductive contactsare outside the light-emitting aperture of the pixel and therefore may be opaque without mitigating overall display efficiency. Conductive contactmay have a transparency that is less than 30%, less than 20%, less than 10%, etc.

5 9 FIGS.- 5 9 FIGS.- 10 16 FIGS.- 66 2 110 26 66 2 66 1 66 2 66 1 14 66 1 45 also show arrangements for one or more pixel definition layers. In the example of, there are at least two pixel definition layers formed from different materials. Pixel definition layer-may fill the trenchesin substrate. Pixel definition layer-may be formed from polyimide or another desired material. An additional pixel definition layer-may be formed from a different material than pixel definition layer-. Pixel definition layer-may define light-emitting apertures for each pixel within display. Pixel definition layer-may include an undercut that creates discontinuities in one or more OLED layersas will be shown and discussed in greater detail in connection with.

5 7 FIGS.- 5 7 FIGS.- 8 9 FIGS.and 66 2 110 66 2 102 42 44 66 2 44 66 2 66 2 42 44 In, pixel definition layer-overflows trenches. In other words, pixel definition layer-extends past an upper surface of overhang layer, reflective conductive layer, and transparent conductive layers(e.g., in the positive Z-direction). In, pixel definition layer-may have portions that are in direct contact with the upper surface of one or more transparent conductive layers. This example is merely illustrative. In another possible arrangement, shown in, the pixel definition layer-may be contained within the trenches such that the pixel definition layer-does not extend past an upper surface of reflective conductive layeror transparent conductive layers.

6 9 FIGS.- 6 FIG. 7 FIG. 8 9 FIGS.and 7 FIG. 44 1 44 2 44 3 44 1 44 2 44 1 44 2 44 1 44 2 In arrangements where a single pixel includes multiple transparent conductive layers (e.g., in), the transparent conductive layers may be formed from a single material or from two or more different materials. As one example, in, transparent conductive layers-,-, and-may all be formed from indium tin oxide (ITO). In, transparent conductive layer-may be formed from indium tin oxide whereas transparent conductive layer-may be formed from indium zinc oxide (IZO). In, transparent conductive layers-and-may both be formed from indium tin oxide (ITO). There may optionally be a titanium oxide liner between two adjacent transparent conductive layers within a given pixel. For example, there may be a titanium oxide liner between ITO layer-and IZO layer-in.

5 9 FIGS.- 44 110 44 110 In, a discrete portion of reflective conductive layeris formed in each trench. This example is merely illustrative and an additional etching step may be performed to remove any portions of reflective conductive layerfrom trenchesif desired.

5 9 FIGS.- 26 110 102 114 42 42 In, substrate(with trenches) and dielectric overhang layercombine to define undercutsthat cause discontinuities in reflective anode portions. This example is merely illustrative. In general, any desired combination of insulating and/or conductive materials may be used to define undercuts that cause discontinuities in reflective anode portions.

5 9 FIGS.- 10 12 FIGS.- 10 FIG. 10 FIG. 26 42 14 14 44 1 22 22 22 44 2 22 22 22 104 22 22 22 104 44 1 44 2 22 22 The examples inof using trenches in substrateto create discontinuities in reflective anode portionsis merely illustrative. Additional embodiments for displaywith pixels having dielectric spacers are shown in.shows an example of a two-cavity arrangement for display. As shown in, a first transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, and a portion in blue pixel-B. A second transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, and a portion in blue pixel-B. A dielectric spaceris patterned to include a portion in red pixel-R, a portion in blue pixel-B, but no portion in green pixel-G. Dielectric spaceris interposed between transparent conductive layers-and-in pixels-R and-B. Each dielectric spacer may be formed from a dielectric material such as silicon dioxide, silicon nitride, silicon oxynitride, titanium oxide, aluminum oxide, etc.

10 FIG. 10 FIG. 10 FIG. 44 1 104 44 1 14 104 44 1 42 120 104 124 120 124 124 122 112 26 As shown in, each dielectric spacer may be formed on and in direct contact with an upper surface of transparent conductive layer-. Dielectric spacermay extend past transparent conductive layer-in a direction parallel to the plane of display(e.g., within the XY-plane of). As shown in, dielectric spacerhas an edge that is separated from the edge of transparent conductive layer-and reflective anode portionby distance. This overhang region of dielectric spacerdefines an undercut. Distancemay be referred to as the width of undercut. Undercutmay have a heightdefined by the separation between the lower surface of overhang layerand the upper surface of substratebetween adjacent pixels.

104 66 1 66 2 66 2 42 44 66 1 66 2 66 1 66 2 66 1 66 2 10 FIG. The overhang of dielectric spacerand corresponding undercut may improve the aperture ratio of the pixels by improving tolerance when depositing pixel definition layers-and/or-. In, pixel definition layer-is formed between adjacent pixels and conforms to the sidewalls of reflective anode portionsand transparent anode portions. An additional pixel definition layer-is formed over pixel definition layer-. Pixel definition layer-defines light-emitting apertures for the pixels. Pixel definition layer-may be formed from polyimide or another desired material. Additional pixel definition layer-may be formed from a different material than pixel definition layer-.

10 FIG. 10 FIG. 66 1 126 126 45 45 126 66 1 45 126 54 shows how pixel definition layer-may include one or more undercuts. The undercutsmay create discontinuities in one or more layers of OLED layersto mitigate lateral leakage of current through the OLED layers.shows how OLED layersmay have discontinuities caused by the undercuts, resulting in some discrete portions of the OLED layers positioned between the undercuts(within the light-emitting aperture of the pixel) and some discrete portions of the OLED layers positioned over pixel definition layer-. Although creating discontinuities in one or more OLED layers, undercutsmay not cause discontinuities in cathode.

10 FIG. 22 44 1 44 2 22 44 1 44 2 104 22 44 1 44 2 104 In, the green pixel-G has a transparent anode portion defined by layers-and-. The blue pixel-B has a transparent anode portion defined by layers-,-, and. The red pixel-R has a transparent anode portion defined by layers-,-, and. The red and blue pixels therefore have optical cavities of a first thickness whereas the green pixel has an optical cavity with a second thickness that is less than the first thickness.

10 FIG. 66 2 26 66 1 126 66 1 126 26 66 2 66 1 126 66 2 66 1 66 2 66 1 In, pixel definition layer-is formed between substrateand pixel definition layer-(which defines undercuts). This example is merely illustrative. In another possible arrangement, the position of these pixel definition layers may be flipped such that pixel definition layer-(which defines undercuts) is formed between substrateand pixel definition layer-. With this type of arrangement, pixel definition layer-(which defines undercuts) may also conform to the edges of the anode stacks. Forming pixel definition layer-above pixel definition layer-in this manner may increase the aperture ratio of the pixels. Pixel definition layer-may be positioned above pixel definition layer-in any of the displays described herein.

10 FIG. 11 FIG. 66 2 124 66 2 22 66 2 42 44 1 104 66 2 22 66 2 42 44 1 66 2 22 66 2 42 44 1 104 66 2 22 66 2 42 44 1 66 2 22 66 2 42 44 1 66 2 22 66 2 42 44 1 66 2 66 2 66 1 66 1 66 2 22 66 2 22 The example inof pixel definition layer-filling the space between adjacent anodes (including undercut) is merely illustrative. In another possible arrangement, shown in, portions of pixel definition layer-are formed adjacent to the sidewalls of the pixel anode portions without completely filling the space between adjacent anode stacks. In red pixel-R, on the left side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-R and transparent conductive layer-. Dielectric spacercovers and is in direct contact with the upper surface of pixel definition layer-in this region. In red pixel-R, on the right side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-R. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In blue pixel-B, on the left side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-B and transparent conductive layer-. Dielectric spacercovers and is in direct contact with the upper surface of pixel definition layer-in this region. In blue pixel-B, on the right side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-B. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In green pixel-G, on the left side of the anode stack, pixel definition layer-conforms to the sidewall of reflective anode portion-G. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In green pixel-G, on the right side of the anode stack, pixel definition layer-conforms to the sidewall of reflective anode portion-R. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. The portions of pixel definition layer-under the overhang portions may be referred to as polyimide plugs. Pixel definition layer-may be interposed between the polyimide plugs of adjacent anode stacks. For example, pixel definition layer-is interposed between the polyimide plug-on the right side of pixel-R and the polyimide plug-on the left side of pixel-B.

12 FIG. 12 FIG. 12 FIG. 10 FIG. 14 44 1 22 22 22 44 2 22 22 22 44 3 22 22 22 104 22 22 22 104 44 1 44 2 104 shows an example of a three-cavity arrangement for display. As shown in, a first transparent conductive layer-is patterned to include a portion in red pixel-R a portion in green pixel-G, but no portion in blue pixel-B. A second transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, but no portion in blue pixel-B. A third transparent conductive layer-is patterned to include a portion in blue pixel-B but no portions in red pixel-R or green pixel-G. A dielectric spaceris patterned to include a portion in red pixel-R but no portions in blue pixel-B or green pixel-G. Dielectric spaceris interposed between transparent conductive layers-and-. Dielectric spacermay be formed from a dielectric material such as silicon dioxide, silicon nitride, silicon oxynitride, titanium oxide, aluminum oxide, etc. The pixel definition layer arrangement inis the same as in.

12 FIG. 22 44 3 22 44 1 44 2 22 44 1 44 2 104 22 22 22 22 In, the blue pixel-B has a transparent anode portion defined by layer-. The green pixel-G has a transparent anode portion defined by layers-and-. The red pixel-R has a transparent anode portion defined by layers-,-, and. The red pixel-R therefore has a thicker optical cavity than green pixel-G and green pixel-G has a thicker optical cavity than blue pixel-B.

13 FIG. 13 FIG. 13 FIG. 14 44 1 22 22 22 44 2 22 22 22 22 44 1 42 22 44 1 22 44 1 44 2 shows an example of a two-cavity arrangement for display. As shown in, a first transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in green pixel-G, and a portion in blue pixel-B. A second transparent conductive layer-is patterned to include a portion in red pixel-R, a portion in blue pixel-B, but no portion in green pixel-G. In, the blue pixel-B has a transparent anode portion defined by layers-and. The green pixel-G has a transparent anode portion defined by layer-. The red pixel-R has a transparent anode portion defined by layers-and-. The red and blue pixels therefore have optical cavities of a first thickness whereas the green pixel has an optical cavity with a second thickness that is less than the first thickness.

14 FIG. 14 FIG. 14 44 1 22 44 2 22 44 3 22 44 1 44 2 44 2 44 3 22 44 3 22 44 2 22 44 1 22 22 22 22 shows an example of a three-cavity arrangement for display. As shown in, a first transparent conductive layer-is patterned to include a portion in red pixel-R, a second transparent conductive layer-is patterned to include a portion in green pixel-G, and a third transparent conductive layer-is patterned to include a portion in blue pixel-B. Layer-is thicker than layer-and layer-is thicker than layer-. Accordingly, the blue pixel-B has a transparent anode portion defined by layer-. The green pixel-G has a transparent anode portion defined by layer-. The red pixel-R has a transparent anode portion defined by layer-. The red pixel-R has a thicker optical cavity than green pixel-G and green pixel-G has a thicker optical cavity than blue pixel-B.

14 FIG. 44 42 150 44 154 150 154 154 152 44 144 44 66 1 66 2 As shown in, each transparent conductive layerhas an edge that is separated from the edge of a respective reflective anode portionby distance. This overhang region of transparent conductive layerdefines an undercut. Distancemay be referred to as the width of undercut. Undercutmay have a heightdefined by the separation between the lower surface of transparent conductive layerand the upper surface of passivation layerbetween adjacent pixels. The overhang of transparent conductive layerand corresponding undercut may improve the aperture ratio of the pixels by improving tolerance when depositing pixel definition layers-and/or-.

13 14 FIGS.and 10 12 FIGS.and In, the pixel definition layers have the same arrangement as in.

15 FIG. 14 FIG. 15 FIG. 11 FIG. 15 FIG. 14 14 22 66 2 42 44 1 66 2 22 66 2 42 44 1 66 2 22 66 2 42 44 2 66 2 22 66 2 42 44 2 66 2 22 66 2 42 44 3 66 2 22 66 2 42 44 3 66 2 66 1 66 1 66 2 22 66 2 22 shows an example of a three-cavity arrangement for displaysimilar to the arrangement of. However, displayinhas the pixel definition layer arrangement of. As shown in, in red pixel-R, on the left side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-R. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In red pixel-R, on the right side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-R. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In green pixel-G, on the left side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-G. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In green pixel-G, on the right side of the anode stack, pixel definition layer-conforms to the sidewalls of reflective anode portion-G. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In blue pixel-B, on the left side of the anode stack, pixel definition layer-conforms to the sidewall of reflective anode portion-B. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. In blue pixel-B, on the right side of the anode stack, pixel definition layer-conforms to the sidewall of reflective anode portion-B. Transparent conductive layer-covers and is in direct contact with the upper surface of pixel definition layer-in this region. Pixel definition layer-may be interposed between the polyimide plugs of adjacent anode stacks. For example, pixel definition layer-is interposed between the polyimide plug-on the right side of pixel-R and the polyimide plug-on the left side of pixel-G.

16 FIG. 16 FIG. 15 FIG. 16 FIG. 16 FIG. 140 138 140 136 138 138 136 140 132 136 138 132 66 2 132 66 2 134 132 136 134 136 138 136 138 136 138 is a cross-sectional side view of an illustrative display with a three-cavity arrangement. The three-cavity arrangement ofis similar to the arrangement ofand duplicate components will not be described again for simplicity. In, each pixel includes via planarization for a via that electrically connects the anode to a control signal contact. As shown in, each pixel includes a first conductive layer that is formed in a via. A second conductive layeris formed over the first conductive layer. Outside of via, conductive layersandare in direct contact with one another. Conductive layermay be interposed between conductive layerand additional conductive components of the anode stack. Within via, planarization layeris interposed between conductive layersand. Planarization layermay be formed from the same material as pixel definition layer-if desired. As one example, both planarization layerand pixel definition layer-may both be formed from polyimide. A dielectric linerformed from silicon nitride or another desired material may be interposed between planarization layerand conductive layer. The linermay improve etching end point detection during the manufacturing process. Conductive layersandmay be formed from titanium, molybdenum, or another desired conductive material. Conductive layersandmay have a transparency that is less than 30%, less than 20%, less than 10%, etc. Conductive layersandmay be formed from a transparent conductive material (e.g., indium tin oxide, indium zinc oxide, etc.) and may have a transparency that is greater than 60%, greater than 70%, greater than 80%, greater than 90%, greater than 95%, etc.

17 FIG. 17 FIG. 16 FIG. 136 138 132 134 146 42 42 146 138 146 146 146 136 138 136 138 is a cross-sectional side view of an illustrative display with a three-cavity arrangement. Each pixel inhas a planarized via formed from conductive layersand, planarization layer, and liner(similar to as shown and described in connection with). Each anode stack also includes a conductive layerthat is formed on a respective reflective anode portion. Reflective anode portionis interposed between conductive layersand. Each conductive layermay be formed from titanium, molybdenum, or another desired conductive material. Conductive layermay have a transparency that is less than 30%, less than 20%, less than 10%, etc. Conductive layermay be formed from the same material as conductive layersandor a different material than conductive layersand.

17 FIG. 22 44 142 1 142 1 42 44 22 44 142 1 142 2 142 1 142 2 42 44 22 44 142 1 142 2 142 3 142 1 142 2 142 3 42 44 44 22 22 22 142 1 22 22 22 142 2 22 22 142 1 142 2 142 3 In, blue pixel-B has a transparent conductive layerformed over a dielectric spacer-. Dielectric spacer-is interposed between reflective anode portion-B and transparent conductive layer. Green pixel-G has a transparent conductive layerformed over dielectric spacers-and-. Dielectric spacers-and-are interposed between reflective anode portion-G and transparent conductive layer. Red pixel-R has a transparent conductive layerformed over dielectric spacers-,-, and-. Dielectric spacers-,-, and-are interposed between reflective anode portion-R and transparent conductive layer. Transparent conductive layertherefore has a uniform thickness in pixels-B,-R, and-G. Dielectric spacer-has a uniform thickness in pixels-B,-G, and-R. Dielectric spacer-has a uniform thickness in pixels-G and-R. Dielectric spacers-,-, and-may be formed from a dielectric material such as silicon dioxide, silicon nitride, silicon oxynitride, titanium oxide, aluminum oxide, etc.

17 FIG. 11 13 16 FIGS.and- 144 26 144 26 144 134 144 134 144 26 144 further shows how a passivation layermay be formed on an upper surface of substrate. Passivation layermay protect substrateduring one or more etching processes (e.g., during a dry etching process for the pixel anodes). Passivation layermay optionally be formed from the same material as linerif desired. As one example, passivation layerand linermay both be formed from silicon nitride. A passivation layermay be incorporated on the upper surface of substratefor any of the embodiments herein (see optional passivation layerin).

17 FIG. 22 22 22 22 In, the red pixel-R has a thicker optical cavity than green pixel-G and green pixel-G has a thicker optical cavity than blue pixel-B.

18 FIG. 18 FIG. 17 FIGS. 18 FIG. 136 138 132 134 22 44 142 1 142 1 42 44 22 44 142 1 142 2 142 1 142 2 42 44 22 44 142 1 142 2 142 1 142 2 42 44 44 22 22 22 142 1 22 22 22 142 2 22 22 142 1 142 2 is a cross-sectional side view of an illustrative display with a two-cavity arrangement. Each pixel inhas a planarized via formed from conductive layersand, planarization layer, and liner(similar to as shown and described in connection with). In, green pixel-G has a transparent conductive layerformed over a dielectric spacer-. Dielectric spacer-is interposed between reflective anode portion-G and transparent conductive layer. Blue pixel-B has a transparent conductive layerformed over dielectric spacers-and-. Dielectric spacers-and-are interposed between reflective anode portion-B and transparent conductive layer. Red pixel-R has a transparent conductive layerformed over dielectric spacers-and-. Dielectric spacers-and-are interposed between reflective anode portion-R and transparent conductive layer. Transparent conductive layertherefore has a uniform thickness in pixels-B,-R, and-G. Dielectric spacer-has a uniform thickness in pixels-B,-G, and-R. Dielectric spacer-has a uniform thickness in pixels-B and-R. Dielectric spacers-and-may be formed from a dielectric material such as silicon dioxide, silicon nitride, silicon oxynitride, titanium oxide, aluminum oxide, etc.

18 FIG. The red and blue pixels ofhave optical cavities of a first thickness whereas the green pixel has an optical cavity with a second thickness that is less than the first thickness.

42 42 42 5 16 FIGS.- 17 18 FIGS.- In any of the embodiments herein, the reflective anode portionsmay comprise aluminum, silver, and/or another desired material. As examples, the reflective anode portionsinmay comprise silver whereas the reflective anode portionsinmay comprise aluminum.

Herein, each transparent layer in the anode stack (e.g., transparent conductive layers, dielectric spacers, etc.) may have a transparency that is greater than 60%, greater than 70%, greater than 80%, greater than 90%, greater than 95%, etc. Each reflective layer in the anode stack (e.g., reflective conductive layers) may have a reflectivity that is greater than 60%, greater than 70%, greater than 80%, greater than 90%, greater than 95%, etc.

The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.